Verifying specifications is still one of the most important undeveloped topics in software engineering. It is important because quite a few critical bugs are caused at the level of domains, requirements, and/or designs. It is also important for the cases where no program codes are generated and specifications are analyzed/verified only for justifying models of problems in real world. In this talk, a survey of our research activities in verifying specifications is given. After explaining fundamental issues and importance of verifying specifications, the proof score approach in CafeOBJ and its applications to several areas are described.